It has long been recognized that soil organic matter is the key to soil fertility. As a nutrient store it gradually provides essential elements which the soil cannot retain for long in inorganic form. It buffers growing plants against sudden changes in their chemical environment and preserves moisture in times of drought. It keeps the soil in a friable, easily penetrated physical condition, well-aerated and free draining, providing young seedlings with an excellent medium for growth. But it has another property, the nature and extent of which have been the subject of argu ment and controversy ever since scientists began to study the soil, and that is its ability to affect growth directly, other than by providing nutrient elements. Any one wishing to learn about these effects has been faced with a daunting mass of literature, some confusing, often contradictory, and spread through a multitude of journals. Individual aspects have been covered from time to time in reviews but there has obviously been a need for a modern authoritative text book dealing with the many facets of this subject, so the publication of this volume is timely. The editors and authors are all specialists in their fields, fully familiar with the com plex nature of soil organic matter and with the particular difficulties arising in any study of its properties. Where controversies exist they have presented all sides of the argument and have highlighted areas where further work is badly needed.

Soil organic matter - a perspective on its nature, extraction, turnover and role soil fertility. Influence of humic substances on growth and physiological processes. Influence of humic subtances on biochemical processes in plants. Phenolic acids in soils and their influence on plant growth and soil microbial processes. Origin, nature and biological activity of aliphatic substances and growth hormones found in soil. Soil enzymes. The soil biomass. Carbohydrates in relation to soil fertility. Soil nitrogen: its extraction, distribution and dynamics. Soil phosphorus. Sulphur in soils and plants. Organic matter and trace elements in soils. Organic farming.

Soil Organic Matter: Its Nature, Its Role in Soil Formation and in Soil Fertility focuses on the contributions of soil organic matter in soil formation and fertility, including weathering, decomposition, and synthesis of humus substances. The publication first elaborates on the main stages in the history of soil humus study and ideas on the composition of soil organic matter and nature of humus substances. Discussions focus on organic substances of individual nature, strictly humus substances in soil organic matter, and humus substances as a complex of high molecular- weight compounds. The text then examines the biochemistry of humus formation, including the role of physical, chemical, and biological factors, origin of humus substances, possible participation of lignin in the formation of humus substances, and the role of oxidizing enzymes in the synthesis of humus substances. The manuscript takes a look at the importance of organic matter in soil formation and soil fertility and the natural factors of humus formation. Topics include the role of organic matter in the weathering and decomposition of soil minerals; role of organic matter in the formation of soil structure; effect of organic matter on the growth and development of plants; and influence of chemical and physicochemical soil properties on humus formation. The publication is a dependable source material for readers interested in the influence of soil organic matter in soil formation and fertility.

Soil organic matter - the product of on-site biological decomposition - affects the chemical and physical properties of the soil and its overall health. Its composition and breakdown rate affect: the soil structure and porosity; the water infiltration rate and moisture holding capacity of soils; the diversity and biological activity of soil organisms; and plant nutrient availability. This document concentrates on the organic matter dynamics of cropping soils and discusses the circumstances that deplete organic matter and their negative outcomes. It then moves on to more proactive solutions. It reviews a "basket" of practices in order to show how they can increase organic matter content and discusses the land and cropping benefits that then accrue.--Publisher's description.

Long-Term Farming Systems Research: Ensuring Food Security in Changing Scenarios presents the legacy and heritage of Long-Term Experiments (LTEs) in Agriculture while also addressing the challenges and potential solutions. The book discusses how LTEs form an important asset in understanding agriculture's significant influence on life on earth. As global governments and development agencies try to achieve the Global Sustainable Development Goals (SDGs) of the United Nations, this book's content is of unprecedented importance, providing insights into the interactions of agricultural production with ecological, economic and societal aspects. In this regard, this book offers a thorough resource of information based on experiences from various ongoing LTEs in different parts of the world. The contextual variety and geographic diversity presented in this book makes it useful for agricultural and environmental scientists, as well as students and educators in such fields. --- From the Editors: "Thanks to the excellent panel of our contributing authors, in this book, we have attempted to offer the widest possible thematic and geographical coverage on LTEs. Experts from different institutions leading LTEs across the globe have provided their perspectives on different aspects of LTEs, not only highlighting the unique knowledge contribution of LTEs, but also discussing the unique challenges of effectively managing LTEs and maintaining their relevance to changing scenarios. We hope that this book will offer something for everyone interested in the history, present and future of our agroecosystem." - Provides a comprehensive resource of information generated in various LTEs across the globe, with a focus on various aspects of farming systems, crop management practices, plant, soil and human nutrition as well as on capacity development - Presents a holistic view on interactions of agricultural production and its relationship to the environment and society - Identifies challenges and lessons learned from different LTEs and provides recommendations for potential solutions

World soils contain about 1500 gigatons of organic carbon. This large carbon reserve can increase atmospheric concentrations of CO2 by soil misuse or mismanagement, or it can reverse the 'greenhouse' effect by judicious land use and proper soil management. Soil Processes and the Carbon Cycle describes soil processes and their effects on the global carbon cycle while relating soil properties to soil quality and potential and actual carbon reserves in the soil. In addition, this book deals with modeling the carbon cycle in soil, and with methods of soil carbon determinations.

This open access book synthesizes leading-edge science and management information about forest and rangeland soils of the United States. It offers ways to better understand changing conditions and their impacts on soils, and explores directions that positively affect the future of forest and rangeland soil health. This book outlines soil processes and identifies the research needed to manage forest and rangeland soils in the United States. Chapters give an overview of the state of forest and rangeland soils research in the Nation, including multi-decadal programs (chapter 1), then summarizes various human-caused and natural impacts and their effects on soil carbon, hydrology, biogeochemistry, and biological diversity (chapters 2–5). Other chapters look at the effects of changing conditions on forest soils in wetland and urban settings (chapters 6–7). Impacts include: climate change, severe wildfires, invasive species, pests and diseases, pollution, and land use change. Chapter 8 considers approaches to maintaining or regaining forest and rangeland soil health in the face of these varied impacts. Mapping, monitoring, and data sharing are discussed in chapter 9 as ways to leverage scientific and human resources to address soil health at scales from the landscape to the individual parcel (monitoring networks, data sharing Web sites, and educational soils-centered programs are tabulated in appendix B). Chapter 10 highlights opportunities for deepening our understanding of soils and for sustaining long-term ecosystem health and appendix C summarizes research needs. Nine regional summaries (appendix A) offer a more detailed look at forest and rangeland soils in the United States and its Affiliates.

The papers in this volume provide a balanced account of developments in soil organic matter research. It focuses on composition and structure, water quality, organic matter turnover, humus quality and fertility, and is essential reading for all those concerned with the environmental aspects of soil conservation and improvement.